pub trait Meter {
// Required method
fn fold(&self, f: &mut dyn FnMut() -> Result<Value>) -> Result<Value>;
}Expand description
The host’s stopwatch.
beck-host may not read a clock — a wasm32-unknown-unknown build has none, and
std::time::Instant::now() on that target is a panic rather than a number — so a host that
wants to know what a fold cost passes one of these in. It is also the reason the fold is the
only thing metered here: it is the one step whose cost is the program’s rather than the
machine’s.